The present invention relates to a mattress, a mattress overlay, or a mattress replacement assembly including an air cushion having air zones for supporting a person, and to a pressure control assembly for controlling the pressure of pressurized fluid contained by the air zones of the air cushion.
Some mattresses, mattress overlays, or mattress replacement systems (hereinafter mattresses) are provided with air sacks to support a person and to provide adjustable firmness characteristics. These air mattresses include one, or several air sacks that are inflated to different pressures to adjust the firmness in selective regions or zones of the mattress. One such mattress is illustrated in U.S. Pat. No. 5,794,288, entitled PRESSURE CONTROL ASSEMBLY FOR AN AIR MATTRESS, which is herein incorporated by reference.
It is desirable for an air mattress to provide different pressure zones of support for a person on the mattress while maintaining sufficient pressure along opposite side edges of the mattress to provide support when the person sits or rests along one of the side edges. In the illustrated embodiment, each air zone is in fluid communication with a manifold having an interior region that is maintained at a constant pressure. The constant pressure of the pressurizing fluid within the manifold may be the same as or may be different from the pressure of pressurized fluid within at least one of the air zones. The illustrated air cushion also includes first and second side bolsters filled with air that extend along opposite sides of the air cushion to help retain a person on the air cushion.
In the illustrated embodiment of the present invention, a mattress assembly comprises an inflatable central support portion having a head end, a foot end, a first side and a second side, and first and second side bolsters coupled to the first and second sides, respectively. The first and second side bolsters each have at least two chambers extending along a longitudinal axis of the first and second side bolsters. At least one of the chambers is a manifold in fluid communication with the central support portion. The manifold is configured to be coupled to an air supply to supply air to the central support portion and the other chambers.
Also in the illustrated embodiment, the inflatable central support and the first and second side bolsters are formed from a plurality of separately inflatable zones. The plurality of zones include a head zone, a shoulder zone, a seat zone, and a foot zone. The illustrated first and second side bolsters each include a top chamber, a central chamber, and a bottom chamber. The central chamber of the first side bolster is illustratively the manifold extending along the first side of the central support portion. The central chamber of the first side bolster is in fluid communication which each of the plurality of zones of the central support portion. The zones of the top and bottom chambers of the of the first and second side bolsters are each in fluid communication with the central support portion through a restricted flow orifice. Illustratively, the zones of the central chamber of the second side bolster are coupled to the top chambers of the second side bolster through a restricted flow orifice. Also illustratively, the bottom chambers in the shoulder zone of the of the first and second side bolsters are coupled to the central support portion by check valves which permit air flow from the central support portion into the bottom chambers in the shoulder zone.
Additional features and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of an illustrated embodiment exemplifying the best mode of carrying out the invention as presently perceived.